This application is a 35 USC 371 application of PCT/DE 00/02057 filed on Jun. 24, 2000.
1. Field of the Invention
The invention relates to metering valves and particularly to such a valve for the metered introduction of fuel that has evaporated from the fuel tank of an internal combustion engine into an intake conduit of the engine, as generically defined by the preamble to claim 1.
2. Brief Description of the Prior Art
One such valve is known from German Patent Disclosure DE 42 44 113 A1, for instance. In this known valve, irritating noise development during valve operation is reduced considerably by at least one damping element. Furthermore, this valve has improved wear resistance, since metal parts moving toward one another are prevented from striking one another, or the impact is at least attenuated.
A marked reduction in irritating secondary noise is already possible with this valve.
Especially in direct-injection gasoline engines that have a relatively high air throughput, however, motor vehicle manufacturers demand further noise abatement in operation of such valves.
It is therefore the object of this invention to refine a valve of the generic type for the metered introduction of fuel that has evaporated from the fuel tank of an internal combustion engine into an intake conduit of the engine, in such a way that further minimization of operating noise is possible, even with an increased air throughput through the valve.
The above objects is attained in an improved valve for the metered introduction of fuel evaporated from the fuel tank of an internal combustion engine into an intake conduit of the engine the outset, this object is attained by the characteristics of because at least one further opening of essentially the same shape as the valve opening and larger than it is opposite the at least one valve opening in the valve closing member and is covered, on its side toward the valve seat body, by the damping element, the damping element on its sealing face disposed in the region of the valve opening has an elastic bearing face, which elastic bearing face resiliently damps the impact of the valve closing member on the sealing face of the valve opening in the valve seat body. As a result, especially effective minimization of operating noise is possible.
In an advantageous embodiment, it is provided that the end face, toward the valve seat body, of the valve closing member is at least partly covered already by the damping element. This enables large-area, highly adherent fastening of the damping element to the valve closing member.
The damping element advantageously protrudes through the at least one further opening and, on the second end face toward the electromagnet, it forms a hump-like sealing face, which at least partly follows the boundary line of the at least one further opening disposed in it. This arrangement not only enables especially simple fastening of the damping element to the valve closing member. In particular, this arrangement also makes it possible for the damping element to be disposed on both face ends of the valve closing member, thus preventing metal-to-metal contact of the valve closing member with the valve seat body or with a sealing face disposed on the electromagnet, upon impact with it.
The damping element is preferably of an elastomeric material. For instance, it can be of rubber, which is vulcanized onto the face end, toward the valve seat body, of the valve closing member and is vulcanized in the at least one further opening and performs not only the damping function but also a sealing function.